Any ideas for cobblestone shed ramp?

Hello, I'm building a 12x10 shed with a mortared field stone foundation. I've got a bunch of jumbo cobblestones that I'm thinking of using for a large ramp on the end to the double doors. The total step up is about 16 inches. Pretty high. I've dug out a square in the area and packed it down in preparation. I've got a bunch of gravel that I could use.

Among the ideas swirling in my head:

Cobblestone wall on each side, somehow sloped to the shed floor.
Cobblestones for the main ramp.
dirt/Pack for the main ramp, between the stone walls.
Skip the cobbles and just use more field stone for the walls.

I've goofed with the stones for a little while, but nothing's jumping out at me. I'd love to not have to mortar these, in case I want to change it, or reuse the nice stone, but I suspect it will be necessary for the walls.